1. Field of the Invention
The present invention relates to a control unit housing, especially for a transmission control module of a transmission of a motor vehicle.
2. Description of Related Art
In transmission control modules for transmissions of motor vehicles, hybrid control units, sensors and at least one plug connection for connecting the transmission control module are used these days on a vehicle cable harness of a motor vehicle. The plug connection for connecting to the cable harness is also designated as transmission plug. The transmission control modules mentioned are currently used while using ATF (automatic transmission fluid), and are exposed to very high temperature fluctuations from a temperature of −40° C. to 150° C. in the vehicle transmission. In order to protect the sensitive electronics deployed in the transmission control module from the aggressive transmission fluid (ATF=automatic transmission fluid), the aim is to accommodate the electronics in a sealed housing. In order to assure sufficient heat dissipation for the electronic components of the transmission control module, in view of the high operating temperatures mentioned, the metallic base area of the control unit housing of the transmission control module is placed against the aluminum housing of a transmission hydraulics system. This means that the metallic base area of the control unit housing contacts the aluminum housing of the transmission hydraulics system, whereby heat dissipation of the waste heat by thermal conduction takes place.
One specific embodiment of a transmission control module that is already in production includes a hermetically sealed control unit housing for an electronic circuit. The hermetically sealed control unit housing itself is made up of a steel base plate that is developed to be flat, and has glazed metal pins, which makes possible the electrical contacting between the circuit and the lead frame using bonding, and a steel cover, which is tightly welded to the base plate. The electrical connection of the glazed metal pin to the sensors and plugs of the electronics module takes place by way of the lead frame. The lead frames are welded onto the glazed pins. Since the glazed pins project perpendicularly from the base plate of the control unit, it is necessary for the contact surface of the transmission hydraulics, required for heat dissipation, to form an elevated area.
Published German patent document DE 196 40 466 B4 describes a metallic substrate part for electronic components or a circuit substrate, as well as a method for producing same. Published German patent document DE 196 40 466 B4 describes a hermetically sealed housing in which the glazed metal pins are not directly glazed into the floor part of the control unit housing, but into two separate parts. The two separate parts are also designated as pin strips, which after their production are welded into the floor plate. This technique has the advantage that only the small pin strips have to be heated during glazing, but the large floor plate does not have to be exposed to the high temperatures that occur during glazing.
One additional specific embodiment of an electronics module, that is currently in mass production, having a sealed control unit housing, is made available based on a flexible printed circuit (FPC=flexible printed circuit) adhered onto an aluminum plate. Published German patent document DE 199 07 949 A1 describes the function of the sealed control unit housing.
A flexible printed circuit board, made, for example, of a polyimide foil, adhesive, copper, adhesive, polyimide foil, is connected by continuous material to the electronic components on a circuit carrier (LTCC), for instance, adhered on. From the LTCC, bonding is carried out directly to the flexible printed circuit board. Onto the flexible printed circuit board, in turn, a plastic cover is laid having an elastomer seal inserted into it, and is rigidly connected to the aluminum plate, for instance, using a riveting connection. In this case, the heat dissipation also takes place to the housing of the transmission hydraulics system. However, because of the planar construction of the control unit housing, no raised area is necessary as was in the design approach according to published German patent document DE 196 40 466 B4.
Published German patent document DE 10 2004 061 818 A1 relates to a control module. In this design approach, a control module is proposed for a transmission of a motor vehicle, which includes a carrier part. On the carrier part there is situated a control unit which has a first housing part and a second housing part and an internal housing chamber situated between the first housing part and the second housing part. At least one flexible conductor foil is provided, which is used for the electrical connection of the circuit part having electrical components that are situated outside the housing inner chamber. The control unit is situated having the first housing part lying on a contact area of the carrier part. The second housing part is situated within the contact area at the first housing part.